1. Field of the Invention
The present invention relates to security devices and, more particularly, to a plug for blocking transmission through a door viewer from a light source.
2. Description of Related Art
For security purposes, and, more particularly, to determine the identity of a person seeking to enter a building, door viewers of various types have been developed. These door viewers generally include a lens system for providing to a person on the inside a wide angle view to the outside. Thereby, the person on the inside has an opportunity to view and identify a person(s) seeking entry prior to permitting entry by opening the door. Generally, the commercially available door viewers for this purpose are adequate in providing the results sought.
The lens system in commercially available viewers does not permit a person outside to view with any clarity a person or features of the room inside the door. However, the door viewer does transmit light from the inside to the outside. If there is no light source optically aligned with the door viewer, ambient light is transmitted through the door viewer from the inside to the outside. In such event, the intensity of the light transmitted is essentially unaffected by a person on the inside looking through the viewer from a short distance removed therefrom. However, if a light source is optically aligned with the door viewer, any blockage of light from such light source to the door viewer will reduce the intensity of the light transmitted through the door viewer. Thus, a person on the outside can readily determine, by the change in light intensity emanating from the door viewer, that a person is present inside in proximity to the door viewer. While it is impossible for the inside person to be recognized due to the optics of the door viewer, the person on the outside will know that a person is inside the building. This information can be used by a thief or burglar as part of the decision making process of whether to burglarize or break into the building. There have also been reported instances of a thief or burglar injuring the person on the inside by driving an icepick or the like through the door viewer when the person on the inside was looking through it, as would be evident by the change in light intensity emanating from the door viewer.
There are available lenses which can be used in conjunction with a conventional commercial door viewer that permit a person from the outside to view with clarity the surroundings on the inside of the door. Thus, the privacy intended by a commercially available viewer is compromised. Such compromise and effect thereof is of particular concern in commercial establishments, such as motels and hotels which have door viewers and wherein the occupants are generally viewable as their activities are normally conducted within the room into which the door opens. Moreover, for a person with criminal intentions the opportunity to view and assess the nature of the occupants prior to committing a criminal act may be of significant benefit and to the detriment of the occupants.
Conventional commercially available door viewers permit transmission of light from the exterior to the interior space of a room into which the door opens. This light transmission will vary from intermittent, partial or complete blockage of light entering the door viewer as persons walk by on the outside. The resulting flickering seen on the inside of a door viewer may be particularly disturbing to a motel or a hotel guest who has turned out the lights and is trying to sleep.
The present invention is directed to a portable or permanently installed blockage for precluding light transmission through a door viewer from the inside to the outside. Furthermore, during daylight conditions, removal of the blockage for purposes for of using the viewer will not provide an indication of whether a viewer on the inside is looking through the door viewer.
It is therefore a primary object of the present invention to provide a portable blockage for precluding light transmission through a door viewer.
Another object of the present invention is to provide a demountable blockage for a door viewer which is attached to the door viewer.
Still another object of the present invention is to provide a selectively usable blockage attached to a door viewer for selectively blocking light transmission through the door viewer.
Yet another object of the present invention is to provide an inexpensive portable or permanently mounted plug for use with a door viewer.
A further object of the present invention is to provide a selectively removable plug for use with a conventional door viewer.
A still further object of the present invention is to provide a plug removable from the inside of a door viewer which does not signal use of the door viewer to a person on the outside.
A yet further object of the present invention is to provide a method for selectively controlling light transmission through a door viewer.
These and other objects of the present invention will become apparent to those skilled in the art as the description thereof proceeds.